Medical institutions have a radiographic apparatus installed therein for taking images of a subject M. As shown in FIG. 15(a), such a radiographic apparatus 51 includes a radiation source 53 and a radiation detector 54 across the subject M in a standing posture. The radiation source 53 is provided for emitting radiation in a horizontal direction along a floor of an examination room. The radiation detector 54 is provided for detecting the radiation transmitting through the subject M. See Utility Model Registration No. 3118190.
The radiation detector 54 has a square detecting surface that detects radiation. The radiation detector 54 is arranged such that the detecting surface thereof is orthogonal to a central axis of a radiation beam B from the radiation source 53 (as if the detecting surface stands). The radiation detector 54 is supported on a strut 52. The radiation detector 54 is movable in a vertical direction along the strut 52. The detecting surface generally has a size to cover a width in a body side direction of the standing subject M in an erect posture. The detecting surface of the radiation detector 54 is not limited to be square, but may be rectangular.
In actual examinations, a region of the subject M to be imaged may be larger than the detecting surface of the radiation detector 54. In such case, radiography is conducted multiple times while the radiation detector 54 is moved in the vertical direction to obtain two or more images. The obtained images are superimposed to generate one image. Such radiography method is often used for imaging a body portion of the subject M.
However, the conventional radiographic apparatus has the following drawback. That is, the conventional radiographic apparatus is not suitable for examinations of scoliosis. Scoliosis is a condition where a backbone bends in a body-side direction of the subject M. In order to diagnose scoliosis, the subject M is imaged while bending in the body-side direction as in FIG. 15(b).
When a symptom of the backbone is observed with the subject M bending as above, a region of the subject M to be imaged (an imaging region of object) becomes larger than the detecting surface of the radiation detector 54. As a result, it is necessary to connect two or more images obtained during vertical movement of the radiation detector 54 to generate a single image. The radiation detector of the conventional apparatus, however, is moved only in the vertical direction. Here, the subject M bends in the body-side direction (i.e., a horizontal direction). Accordingly, the body portion of the subject M does not extend in the vertical direction. Consequently, the body portion of the subject M extends in a direction different from a moving direction of the radiation detector 54. Consequently, the body portion of the subject M may be partially out of an imaging field of view of the radiographic apparatus 51.
Specifically, as shown in FIG. 15(b), the radiographic apparatus 51 cannot have the imaging region with a width larger than a width W1 of the radiation detector 54. Thus, radiography cannot be conducted to a width W2 of the body portion of the bending subject M out of the width W1. According to the conventional configuration, although the subject M lies within the width W2, the portion of the subject M within the width W2 cannot be imaged.
This invention has been made regarding the state of the art noted above, and its object is to provide a radiographic apparatus that can conduct radiography for an appropriate imaging region although a subject bends in a body-side direction.